Electric delayed-action switches



Oct. 4, 1955 A. M. ALLEN 2,719,887

ELECTRIC DELAYED-ACTION SWITCHES Filed Oct. 1, 1955 l\ R jW-o A United States Patent ELECTRIC DELAYED-ACTIQN SWITCHES Alfred Massey Allen, Watford, England, assignor to Rotax Limited, London, England Application October 1, 1953, Serial No. 383,631

1 Claim. (Cl. 200-35) This invention relates to electric switches of the kind in which a delayed-action is obtained by an escapement mechanism acting on a spring-actuated motive mechanism.

For some purposes it is desired to be able to effect an actuation of the switch independently of the escapement mechanism. Or, in the event of failure of supply of current to the system controlled by the switch, while the switch is in action, it may be desired to effect instantaneous and automatic movement of the switch to its normal position by the motive mechanism. The object of the invention is to enable such requirements to be met in a simple and reliable manner.

The invention comprises a switch of the kind specified having in combination therewith a spring-loaded clutch for securing to its spindle a pinion situated between the escapement mechanism and the motive mechanism, and a spring-loaded clutch-releasing member under the control of an elcctromagnet, the arrangement being such that so long as the electromagnet is energised, the clutch is active and the mechanism operates normally, but on interruption of the electromagnet current, the clutch is released for isolating the escapement mechanism from the motive mechanism to enable the latter to actuate the switch instantaneously.

The accompanying drawing illustrates diagrammatically a switch embodying the invention.

Referring to the drawing, the spring actuated motivemechanism (which may be energised electrically or otherwise) is indicated by a, and the escapement mechanism by b, the latter being connected to the former by a train of gear wheels c. Included in this train is a pinion d which is freely mounted on a spindle e driven by the escapement mechanism. This pinion is placed between a collar 7 formed on or secured to the spindle and a collar g which is loaded by a spring h and is slidable on the spindle, the two collars forming a friction clutch for re- "ice leasably securing the pinion d to the spindle. In association with the clutch is arranged a lever i which is loaded by a spring 1' acting on a plunger k. The lever i is operable in opposition to the spring j by an electromagnet m which is energised by current received from the circuit controlled by the switch.

In the arrangement shown the lever i acts on the collar g, and when the electromagnet is in action (as shown in the drawing) the lever is retracted from the collar g against the action of the spring 1', thereby allowing the pinion d to be gripped between the collars j", g under the action of the spring h. When the current through the winding of the electromagnet is interrupted, the spring 1', (acting through the plunger k) forces the collar g against the action of the spring h in the direction for releasing the pinion d.

The switch is operated by the spindle n of the motivemechanism, and comprises a plurality of cams 0 mounted on the spindle n and co-operating with resilient arms p adapted to control a plurality of electric circuits in a desired sequence. Normally the rate of rotation of the spindle n is controlled by the escapement mechanism, but in the event of accidental or intentional interruption of the current which energises the electromagnet m, the pinion d is freed, and the motive-mechanism can then rotate the cams 0 rapidly to an off or other predetermined position.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

An electric switch comprising in combination a springactuated motive mechanism, an escapement mechanism, a spindle operatively connected to one of the two mechanisms, a pinion freely mounted on said spindle and operatively connected to the other of said mechanisms, a releasable spring-loaded clutch for securing said pinion to said spindle so that the operation of said motive mechanism is retarded by said escapement mechanism, springloaded means for releasing said clutch, and thereby enabling said motive mechanism to operate unretarded by said escapement mechanism and an electromagnet for rendering said spring-loaded means ineffective, whereby so long as said electromagnet is energised said clutch serves to connect said escapement mechanism to said motive mechanism, but when said electromagnet is deenergised said clutch is released for isolating said escapement mechanism from said motive mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 

